/*
* Copyright 2013 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.xd.dirt.stream.dsl;
/**
* A lookup environment is used to resolve a stream. Stream resolution chases down references to substreams or
* referenced labels/modules.
*
* Note: For the initial implementation we use the stream parser class itself but that means when xd-admin is restarted
* it will not be able to resolve streams. The stream parser also does not know when streams are deleted. Eventually the
* proper implementation will be based on the stream directory.
*
* @author Andy Clement
*/
public interface StreamLookupEnvironment {
/**
* Look up a previously defined stream by name, returns the parsed AST for it.
*
* @param name name of the stream
* @return AST for the stream
*/
StreamNode lookupStream(String name);
}